The present invention generally relates to a structure of a grommet consisting of a soft grommet body and a resinous lock member, and more particularly, to a grommet having a structure for preventing the grommet body fitted to the resinous lock member from being released therefrom.
FIG. 1 is a perspective view illustrating parts of a conventional grommet, FIG. 2 is a vertical sectional view illustrating the assembly thereof, and FIG. 3 a rear elevation. The conventional grommet shown is composed of a soft grommet body A and a hard resinous lock member B. The grommet body A has a protrusively provided tube 2 serving as an electric wire insertion hole formed in an inner periphery of a base 1 assuming a hollow disc-like configuration. A peripheral wall 3 is crookedly formed along an outer periphery of the base 1; and the tip portion of the peripheral wall 3 is further bent inwards, thus providing an annular supporting portion 4.
An inner peripheral surface of the tube 2 is provided with a plurality of lips 5 by which an electric wire inserted into the tube 2 is sealed. For waterproofing, tapes T are wound both on the electric wire and on the tube 2.
The base 1, the peripheral wall 3 and the supporting portion 4 of the grommet body A cooperate to internally form an annular recess 7 to which a substrate 8 of the resinous lock member B is attached.
The resinous lock member B includes the hollow disc-like substrate 8 on which a square pillar 9 is mounted. A bottom wall 10 assuming a hollow disc-like shape is fitted to the square pillar 9.
Four stop members 11 each having a stop stepped-portion 11a are vertically provided on the outer periphery of the bottom wall 10 so as to be directed to the substrate 8.
The stop members 11 are fitted in, creating elastic flexure, when the resinous lock member B is inserted into a hole of a pannel P, resulting in elastic enagement of the stop stepped-portions 11a. The resinous lock member B is thus .seized by the pannel P. Accordingly, the square pillar 9 is formed to have four angular portions 9a middled between the contiguous stop members 11 so as not to interfere with the flexural deformation of the stop members 11.
The supporting portion 4 of the grommet body A, as depicted in FIG. 1, serves to support, with a dimension l.sub.1 an entire outer periphery of the substrate 8, thus keeping the engagement of the resinous lock member B with the grommet body A (see FIGS. 4 and 5). The reference numeral 12 designates an annular outer peripheral lip, provided along the peripheral wall 3, for protecting the hole of the pannel P from the permeation of water by virtue of its close-contact with the pannel P.
The thus constructed grommet is installed in the following manner.
The grommet body A is, as illustrated in FIG. 2, fitted in the resinous lock member B, and the electric wire (wire harness) 6 penetrates the bottom wall 10 and the substrate 8 and is inserted into the tube 2.
Next, the resinous lock member B is inserted into the hole P.sub.1 formed in the pannel P while being guided by the square pillar 9. At this time, each of the stop members 11 impinges upon an edge of the hole P.sub.1, thereby producing flexure. Just when the stop stepped-portion 11a is overlapped with the hole P.sub.1, the stop stepped-portion 11a is brought into press-contact with the edge of the hole P.sub.1 by pint of elastic force of the stop member 11, whereby the resinous lock member B is seized by the pannel P. The outer peripheral lip 12 of the grommet body A fitted in the resinous member B is tightly secured to the pannel P, causing elastic deformation.
In this way, the grommet functions to provide the waterproofing between the electric wire 6 and the pannel P.
The resinous lock member B fitted in the annular recess 7 formed in the grommet body A is held in a fitstate by the supporting portion 4. For instance, however, where a tensile force acts on the electric wire, the grommet body A is stretched together with the electric wire 6, thereby causing elastic deformation of the grommet body A. Then, the periphery of the supporting portion 4 is lifted with the result that the seizing force of the substrate 8 is lost. Hence, there arises such a problem that the grommet body A comes off the substrate 8.
The present invention has been made to obviate such problems.